Control system for phonographs



Oct. 22, 1940. c; cu s CONTROL SYSTEM FOR PHONOGRAPHS Filed Nov. 28,1959 azrnopucs REVERSING CONTROL INVENTOR Roy'er C. Cal-118 w V WATTORNEY Patented Oct. 22, 1940 CONTROL SYSTEM FOR PHONOGRAPVHS Roger 0.Curtis, Milford, com,- assignorto Dieg I taphone Corporation,Bridgeport, poration of New York Conn, a cor- Application November 28,'1939, Serial No. 306,453 1 15 Claims,

This invention relates to electric dictating machines and moreparticularly to a controlsystem for operatingsuch machines, and to anindicating system for informing the operator of the operable conditionof the machine at all times. This invention is particularly applicableto electricdictating machines of the type illustrated and described inPatent No. 2,143,819 for transforming sound Waves into electricalimpulses, amplifying these impulses, recording them on suitable recordblanks, or for reproducing sounds recorded on record blanks byconverting the soundtrack into electrical impulses, amplifying theseimpulses and retransforming them into sound waves. In such electricdictating machines it is essential that the amplifier be in operablecondition in order that complete dictation may .be satisfactorilyrecorded or reproduced. It is therefore desirable that such. machines beprovided with a control system which is responsive to the operativecondition of the amplifier and is so interconnected or interlocked withthe remaining elements of the dictating machine that these elements arenot'permitted to operate, or at least some indication is given, when anattempt is made to operate the machine when it is not prop- .erlyconditioned for satisfactory operation. If,

forexample, one of the amplifier vacuum tubes is burned out or if a D.C. amplifier is used and is connected to a D. C. power supply withreversed polarity, then it is desirable that this be indicatedimmediately to prevent the operator from dictating a long dictationbefore he discovers that the amplifier and therefore the machine is notin operative condition.

Furthermore, because dictating machines are frequently used onlyintermittently over long periods of time, for efficient operation it ispreferable that a minimum amount of electrical power be supplied to themachine during standby periods. For this latter reason it is desirableto disconnect the motor from the power supply, to open theplate powersupply circuit of the amplifier, and to insert a resistance in serieswith the heaters of the vacuum tubes ofthe amplifier and rectifier, sothat the only input to the machine during standby periods is a smallportion 'of the heating current necessary for normal operation of thevacuum tubes.

In an electric dictating machine arranged in this manner, when the mainpower switch of the dictating machine is closed, suificient current ispassed to heat the heaters of thetubes almost to operating condition sothat they will always be warm'and capable of heating up to the full fullemission: temperature. V I the amplifier is .not operativeandseveralfsylla not operative.

(Cl. 1 -'79100.4) o. V. operating temperature in a fewseconds; uponapplication of full heating current. At thesame time, an indicator lamp,preferably red, may be lighted to show that the machine is in standbycondition. When the dictator lifts the speaking tube tocommence'dictating, the resistorfin'serie's with the vacuum tube heatersis short-circuited, thus supplying full operating current to theseheaters, and at the same time the plate power supply'circuit of theamplifier is closed-Ina few seconds the cathodesare-heated to fullemissiontemperature, the mandrel-driving-motor is ately, before thecathodes have'reached th'eir When this occurs,

bles of the dictation may be lost'before the am}- plifier heaters reachoperating temperature; is especially true at the beginning of a periodj'ojf dictation following .a period of disuse with electriccircuitsdeenergiz ed. In the latter situ ation, the'operator may turn onthe mainypower supply switch and start 'to dictate immediately.

In this'case, it may take the amplifier almost a ing .or' green lightwould not light for apredetermined periodof time after. theswitch isclosed, thus; warning the operator that the machine is Such anarrangement has the disadvantage that if the operator has just turnedthe machine off and then turned it on-imme di ately thereafter, the,thermostatic switch relay might not have cooled sufliciently tofopenthecircuitto the operating or green light. Thus theoperatonse'eing thegreen light, wouldfcomwhen the machine is only used intermittently overa considerable period of time, and which permits .mence dictationimmediately-whereas the amplij-fier tubes might havecooled'sufiicientlyto render following specification and may be morereadily understood by reference to the -accompanying drawing which showsa schematic diagram of an 15 electric dictating machine-embodyingthe'present invention.

A record-supporting mandrel 2 carrying a cylindrical record blank 4 isdriven through suitable gearing and drive shafts, represented by thedot- 20 ted line 6, and a clutch mechanism, generally-inli a ed a ifliba i ab univ l m t 0.- A combined microphonedoudspeaker l 2, mounted in a;.speak;ing tube l4, isconnected by a suitable h el e b ihroi ia ere inai 1. m 2, h 1 .1mm preampl fie .Ouipub o thempli er 2 i ;9Qnl e thro thes im an a hie ded cabl t suitable electromechanical recorder-reproducerunit 28. h un im n n th m h ne J 3 9 are converted intoelectricahimpulses which are am l fi d br h am fie a thence r e' d o thr cord-bl k yp e a q c ii e61 cmm chan cal s fi onu ait 3 doting q T widi L V c. M ,3 button or switch 3 0 ,;,mounted on a speaking ,tube.l.4,.operates the clutch 8 througha suitable transmission linkage,represented by the dotted line 32," to start and stop the rotationi ofthe mandrel 2 and the record blan 4 at ith'ewill of 40 the .dictator. Acontrol '1''ver;a a, associated with the recorder-reproducer nnit 28, isadapted'to inQYe this u n itl28 fromrecording to reproducing ip ositionvwhenlit is desir edTtoj reproduce the s oulidstrecorded on therecorid'lblank Qperation of..,this lever arrangementjlals'osimultaneously operates reversing'switch lfthroiigh a .n ka' issndaiver; asjt' connect the translationunit". 2a to the input 2,0 or the.amplifierf22 and: to connect the microphone-loudspeaker.unit

. ac a loudspeaker tot reproduce the sound re- Lcdfdedon record blank74. Ahariger' 37,ha.ving a'.hook"3f9 at one end fis pivoted at "38"on'th'e frame of the' dictating'machinei '(hot shown), and i'sf adaptedto support the speaking tube-l (when thenrfachi'ne is not'in use. Thishanger 3"Itilts amercury switch by means *of -a' suitable link- 'age4-ltoopen-th'e circuits-therethroughwhen the speaking tube I4 is hung -o'nthe hook 39, inthe position shown in the drawing. '-Ihe=-movement of thehanger 31' limited by stops fl and'it is 'normallybias'ed by-aspring--44 so that hook 39 is ""n its uppermost position when thespeaking tube "44'- is removed from the hook 39. The mercury :65 switchlll has three electrodes 45, 46,- and- 41,

*whiclrare connected together by the poolof me'roux-y in the switch whenthe hook 39 is held in "its uppermost pos'ition-by the spring 44 againstthe stop 42,to closezeertain' circuits in the power supply and controlportions of the machine, as will-ihereinaf-ter be described. YElect'rical power for' the :dicta'ting .machine. is :su'pplied from v astandardr1 10-.volt .A. C. .or. D. .C. vsupply line-:50 through a :mainline :or standby switch; 52 Land xa fuse. 154 .to ;.the -control.andindieating portion of the machine, generally indicated at 55, andthe power supply or rectifier unit, generally indicated at 58. One sideof this power supply is connected through wires 59 and 60 to .oneelectrode 45 of mercury switch 40, whence, 5

when the mercury switch is closed, it is connected through a secondelectrode 41 and a wire 62 to the anode 64 of a rectifier tube 66. Thecathode 68 ofrectifier 65 is connected to a capacity and inductancefilterto the plate cir- 10 cuits of the amplifier 22 to supply platepower to the anodes of the amplifier tubes. The same side 59 ofthe'power supply is also connected through a'wire'12 and seriesresistances 14 and 'lfi through-the series connected heater elements1-8-of the vacuum tubes in amplifier 22 and the "heater element 80 ofrectifier 66 back to the other side of thepower supply through wire 82.The

third electrode 46 of the mercury switch 40 is connected through a wire84 to the connection between resistors 14 and 16, so that resistor I4 isshort-circuited when .the mercury switch is in closed position.When'bothresist'ors 14 and 1.6 are connected in series withheate'rs 18and 80 only a small or standby current flows through these heaterelementswhich is just sufficient to keep the elements warm,'but, notenough to bring them to full operating temperature. When the mercuryswitch '40 is closed by removing speaking tube [4 from hook 39, thusshorti'ngresi'stor T4, the resistance "16 in series with the heater ele-'ments '8 and8i) is of such a value that theffull operating heatercurrent flows in this circuit to bring the cathodes to full emissiontemperature.

In the arrangement, thus'far described, when the operator removes thespeaking tube l4 from the hook3'9, thus'c'losing the circuits'throughthe mercury switch 40;resistor '14 in the -heating circuit isshort-circuited, thus applying full heating current to the'heater's Band80. At the same time,'the plate '64 of rectifier'SG isconnected'to oneside of the line through wires'62, '60; and 59 to supply plate potentialto the amplifier" 22. Amplifier 22 is thus'rendered fully operativeassoon as the heaters 18 and80 reach fulloperating temperature, and thenthe dictating machine maybe usedto record or reproduce as'desired.

However, for a'short' period of time after the speaking tube [4is'removed fromjhook 39,'while the heaters 18 and 80' are still comingup to temperature, the amplifier is inoperative, and if dic- 'tation isattempted during this period a-portion jof the dictation will notberecorded.

To prevent such -a"'loss" of dictation, in accordancewith thisinvention, a control arrange.- ment is provided which is "interconnectedwith the motor In to prevent its operation after the speaking tube 14has been lifted from hook 39 until "the heaters ,18'and 80 have heatedtheir respective cathodestohfull emissive temperature so that: theamplifier is in operative condition. In addition, ,a green indicatorlight .99 is also provided which lights only after such operativecondition has been attained. This is accomvplished by providing acontrol relay, generally M indicatedat 86, in the controhportion :56 ofthe instrument. Thisrelay 'is :actuated bya .sole- ,noid 88 whichisconnected to .wire '82 from acne side of the supply line through-aresistor '90 to theoathode=68 of 'the'rectifier lili. This relay 00 86isprovided with a pairof contacts 9| and 92, normally closed due totheaction of a biasing zspring -96, forming a single-pole single-throw,switch which is opened upon energization of .solenoidBB, and threeothercontacts ;93, 94,

and forming a single-pole double-throw switch which normally makescontact between contacts 93 and 94 due to the action of spring 96, butwhich opens this circuit and makes contact between contacts 94 and 95when the solenoid 88 is energized. These contacts are operated in thismanner by an armature 9.1 associated with the solenoid 88.

Contacts 9! and 92 are connected acrossresistor 99 to short circuititwhen the. relay,85 is deenergized so that the initial current 1flowingthrough solenoid 88 is greater than its normal operating current, thusinsuring rapid operation of the relay when it is energized but keepingthe load on rectifier 66 due to the relay at a minimum. Contact 94 ofthe secondgroup of contacts is connected to one side of the supply line59 through wire 59. The upper, or normally closed contact 93, isconnected to a..red indicator lamp 98 which in turn is connected :to theother side of the supply line 59 through wire 82. The lower contact 95,which connects with contact 94 upon energization of the solenoid 88, isconnected to thegreen indicator lamp 99 which is also connected to wire82. Contact 95 is also connected to one side of the universal drivingmotor l9, the other terminal of this motor being connected to wire 82.Thus motor. l9 cannot operate until amplifier 22 is in operativecondition as shown by energization of. solenoid 88.

In the operation of the dictating machine herein described, when theoperator wishes to have the machine ready for operation he closes themain line switch 52 which puts the instrument in standby condition. Thispermits a subnormal current to fiow through the heaters 78 and 89, thuspreparing them for rapid heating to operating temperature when actualoperation is desired. Likewise, this causes current to fiow from oneside of the power, supply-59 through wire 59, contact 94,.contact 93,and the red signal lamp 98 back through wire 82 to the other side of thesupply line 59, thus causing the red signal lamp 98 to light andindicate the standby condition. When the operator wishes to dictate andremoves the speaking tube l4 from the hook 39, this tilts mercury switch49, closing the circuit between electrodes 45, 49, and 41, thusconnecting plate 64 of rectifier 66 through wires 62, B9, and 59 to oneside of the power supply and also shorting out resistor 14 to permitfull operating current to pass through the heaters 18 and 89. When thisfull operating current has been applied to the heaters for a sufficientlength of time to heat the cathodes to emissive temperature, currentflows through the rectifier 96 from one side of the power supply linethrough wires 59, 69, and 92, rectifier 66, contacts 9| and 92 of relay88, and hence through solenoid 88 to wire 82 on the other side of thesupply line 59, thus energizing the sole noid 88 and thereby attractingarmature 96. This breaks the circuit between contacts 93 and 94 thusextinguishing the red indicating lamp 98, breaks the circuit betweencontacts 9| and 92 thus inserting resistance 99 in the circuit ofsolenoid 88, and makes the circuit between contacts 94 and 95 from oneside of the supply line through wire 59, contacts 94 and 95, throughindicator lamp 99 and motor l9 connectedin parallel, to wire 82 on theother side of the supply line 59. This starts the motor, and also lightsthe green indicating lamp 99 to show the operator that the machineis,;instantly ready for recording or reproducing.

The amplifier tubes for the amplifier 22 ar preferably chosen withcathode heating rates substantially equal to or less than that of rectias cathode heating is concerned, and inasmuch as relay 96 is'directlyresponsive to the fiow of "current through rectifier 69, theindicatorlamps 99 and 99 operate in immediate response to the actual condition ofthe amplifier 22 at all times. Thus, the operator at all times knows thecondition of the dictating machine irrespective of whether he has justturned on the main line switch 52, or whether he has just hung thespeaking tube [4 on hook 39, or removed it therefrom.

As many embodiments might be made of the above invention, and as manychanges might be made in the embodiment above described, it is to beunderstood that .all structure hereinbefore described as shown in theaccompanying drawing is to be considered as illustrative only and not ina limiting sense.

I claim:

1. In a control system for an electrical dictating machine adapted forintermittent operation and equipped with electronic devices requiring aperiod of time after the application of electric power to said devicesto reach full oper-,

ative condition, in combination, means for applying electric power to atleast one of said electronic devices, control means for renderingoperative certain elements of said dictating machine,

and means operative after the operation of said power-applying means andresponsive to thenormal flow of power through atleast one of saidelectronic devices for permitting operation of said control means torender operative said dictating machine elements.

2. In a control system for an electrical dictating machine adapted forintermittent operation and equipped with electronic devices requiringa'period of time after the application of electric power to said devicesto reach full operative condition, in combination, control means forcontrolling the application of electric power to at least one of saidelectronic devices, motor means for driving said dictating machine, andmeans operative after the operation of said control means and responsiveto the normal flow ofpower through at least one of said electronicdevices for permitting operation of said motor means.

3. In a control system for an electrical dictating machine adapted forintermittent operation and equipped with electronic devices requiring aperiod of time after the application of electric power to said devicesto reach full operative condition, in combination, means for applyingelectric power to at least one of said electronic devices, interlockmeans for preventing operation of certain elements of said dictatingmachine, and means operative after the operation of said power-applyingmeans and responsive to the normal flow of :powerthrough at least ationof said dictating machine elements. i p

4. In a control system for an electrical dictating machine'adapted forintermittent operation and equipped with electronic devices requiring aperiod of time afterthe application of electric power to said devicesto'reach full operative condition, in combination, control means forcontrolling the application of electric power :to at least one of saidelectronic devices, motor means for drivingsaid dictating machine,interlock means for preventing operation of said motor means, and-meansoperative after the operation of .said control means and responsive tothe normal flow of power through at least one of said electronic devicesfor rendering said inter- .loclcmeans inoperative to permit.operation'of'said motor means. Y

5. In a control system for an electrical dictating machine adapted forintermittent operation and havingan amplifier unit equipped withelectronic devices requiring a period of time after the application ofheating current for the oathodes of said devices to reach full operativeemissivity, in combination, control means for controlling theapplication of cathode heating current to at least one of saidelectronic devices, an electrically operated dictating machine element,and means operative after the operation of said control means andresponsive to the fiow :of emission current through .at least one ofsaid electronic devices for preventing operation of said dictatingmachine element until said emission current reaches its normal operatingvalue.

6. In a control system for an electrical dictating machine adapted forintermittent operation and having an amplifier unit equipped withelectronic devices requiring a period of time after the application ofheating current for the cathodes of said devices to reach full operativeemissivity, in combination, control means for controlling theapplication of cathode heating cur- J rent to at least one of saidelectronic devices,

motor means for operating said dictating machine, and means operativeafter operation of said control means and responsive to the flow ofnormal emission current through at least one of said electronic devicesfor operatively connecting said motor means to a source of power topermit operation of said dictating machine.

7. In a control system for an electrical dictating machine adapted forintermittent oper- 'said electronic tubes, control means for connectingsaid circuit to said anodes, and means responsive to an attempt tooperate said dictating machine for operating said control means to applyoperating potentials to said anodes to render said amplifier operative.

8. In a control system for an electrical dictating machine adapted forintermittent operation and having an amplifier unit equipped withelectronic tubes having anodes, cathodes and control elements, incombination, a circuit for supplying subnormal heating current to thecathodes of said electronic tubes, another circuit for supplyingoperating potentials to the anodes of said electronic tubes, controlmeans for adjusting said first circuit to supply normal heating currentto said cathodes and for connecting said second-circuit to said anodes,and :means responsive to an attempt to operate said dictating machinefor operating said control means to render said amplifier operative.

9. In a control system for an electric dictating machine adapted forintermittent operation and having'an amplifier unit equipped withelectronic devices having anodes, cathodes and control elements whichrequire a period of time after the application of heating current forthe cathodes of said devices-to reach full operative emissivity, incombination, acircuit for supplying subnormal heating current to thecathodes of said electronic devices, a second circuit for supplyingoperating potentials to the anodes of said electronic devices, controlmeans for adjusting said first circuit to supply normal heating currentto said cathodes and for connecting said second circuit to said anodes,motor means for operating said dictating machine, means responsive to anattempt to operate said dictating machine for operating said controlmeans, and means operative after the operation of said control means andresponsive to the flow of emission currentthrough at least one of saidelectronic devices for preventing operation of said motor means untilsaid emission current reaches its normal operating value.

10. Ina control system for an electrical dictating machine adapted forintermittent operation and having an amplifier equipped with electronicdevices requiring a period of time after the application of heatingcurrent for the cathodes of said devicesto reach .full operativeemissivity, in combination, means for controlling the application ofcathode heating current to said electronic devices, indicator means, andmeans operative after the operation of said first-named means andresponsive to the flow of normal emission current throughiat least oneof said devices for operating said indicator means to indicate that saidamplifier is ready for instant operation.

11. In a control system for anelectrical dictating machine adapted forintermittent operation and having an amplifier equipped with electronicdevices requiring a period of time after the application of heatingcurrent for the cathodes of said devices to reach full operativeemissivity and a rectifier having substantially similar heatingcharacteristics for supplying power to said amplifier, in combination,means for controlling the application of cathode heating current to saidelectronic devices and said rectifier, an indicator device, and meansaoperative after the operation of said first-named means and responsiveto the ijlow of current through said rectifier for operating saidindicator device to indicate that said amplifier is in instantlyoperative condition.

12. In a control system for an electricaldictating machine adapted forintermittent operation and having an amplifier equipped with electronicdevices requiring a period of time after the application of heatingcurrent for the cathodes of said devices to reach full operativeemissivity and a rectifier having substantially similar heatingcharacteristics for supplying power to said amplifier, in combination,means for controlling the application of cathode heating current to saidelectronic devices and said rectifier, an indicator light, a relayincluding'an energizing solenoid and a plurality of contacts, saidsolenoid being connected in series with said rectifier, said contactsbeing connected in a circuit with said indicator light and a source ofelectrical power, whereby said relay is actuated after operation of saidfirstnamed means to operatesaid light to indicate that said amplifier isin instantly operative condition.

13. In a control system for an electrical dictating machine adapted forintermittent operation and having an amplifier equipped with electronicdevices requiring a period of time after the application of heatingcurrent for the cathodes of said devices to reach full operativeemissivity, in combination, a circuit for supplying subnormal heatingcurrent to the cathodes of said electronic devices, control means foradjusting said circuit to supply normal heating current to saidcathodes, means responsive to an attempt to operate said dictatingmachine for operating said control means, signaling means, and meansoperative after said control means and responsive to the flow of normalemission current through at least one of said electronic devices foroperating said signaling means to indicate that the amplifier is inoperative condition.

14. In a control system for an electrical dictating machine adapted forintermittent operation and having an amplifier equipped with electronicdevices requiring a period of time after the application of heatingcurrent for the cathodes of said devices to reach full operativeemissivity and a rectifier having substantially similar heatingcharacteristics for supplying power to said amplifier, in combination,means for controlling the application of cathode heating current to saidelectronic devices and said rectifier, an electrically operateddictating machine element, a relay including an energizing solenoid anda plurality of contacts, said solenoid being connected in series withsaid rectifier, certain of said contacts being connected in a circuitwith said dictating machine element and a source of electrical power, anim pedance connected with others of said contacts and said solenoidwhereby said relay is actuated after operation of said control means topermit operation of said dictating machine and said impedance .isconnected in series with said solenoid to decrease the load on saidrectifier.

15. In a control system for an electrical dictating machine adapted forintermittent operation and having an amplifier equipped with electronicdevices requiring a period of time after the application of heatingcurrent for the cathodes of said devices to reach full operativeemissivity and a rectifier having substantially similar heatingcharacteristics for supplying power to said amplifier, in combination, acircuit connecting the cathode heaters of all of said electronic devicesand said rectifier in series, means for controlling the application ofcathode heating current to said heater circuit, a dictating machineelement, and means operative after the operation of said control meansand responsive to the normal flow of current through said rectifier forpreventing the operation of said dictating machine element upon failureof the heaters of any of said electronic devices.

ROGER C. CURTIS.

